In recent years, vehicle control is in development in a variety of aspects including driving support functions and autonomous driving functions. Accordingly, the scale of application programs such as vehicle control programs and diagnosis programs installed in electronic control units (also referred to as ECUs) of the vehicle is increasing. Because of version upgrades for function improvement etc., the opportunity to rewrite (reprogram) the application programs on the ECUs is also increasing.
With the development of communication networks etc., a connected-car technology is also in development. Under such circumstances, a technology for a center to distribute ECU update programs to vehicle apparatuses over-the-air (OTA) and for the vehicles to write the update programs is desired.